Hot air furnace



June* I5, 1942 c. BLAIR 2,286,665`

I HOTVAIR FURNACE Filed Aug. 14,- 1940 2 sheets-sheet 1 .INJIKNN .uw N HW Y NNLINN N June. 16, 1942. C, B| A|R HOT AIR FURNAC Filed Aug. 14, 1940 Sheets-Sheet' 2 Patented June 16,1942 I UNITED STATE S! PATENT oFFlcE 'rms invention relates to a not air furnace and has for an object to provide a furnace in which the gasespass from an enclosed radiant combustion lhamber through oppositelydisposed hori" zontal tubes arranged. in zigzag l:fashion upwardly to opposite sides of the furnace and terminating in a common header from which'the i gases pass into the chimney, tol 'more uniformly heat air draft passing through the furnace at every point thereof than hitherto possible in conr venti'onal hot air furnaces,

A further object is to provide' a hot air lfurnace' in which the air is drawn in from the top of the furnace through a grille which divides the air draftinto ne streams, the air passing around the convolutions of the tubes to be uniformly heated at every part-of the furnace, andthen being drawn from the furnace by a fan to be supplied to the rooms to be heated, the air thus passing from the furnace through agrlle, both grilles and the suction of the fan tending to rarefy the air draft and speed it up to promote Figure 5 is a plan view of one ofthe sections of the combustion chamber.

Figure 6 is a detailelevation of vone of the iins which are secured to the horizontal tubes, with the parts separated. n

Figure 7 is a cross sectional view of one of the fins in position on a tube.

Referring now to the drawings in which like -characters of reference designa'te similar parts in the ,various views, I0 designates the casing of f the furnace within which is disposed a combusmore uniform heat thereof than Where the air is forced through the furnace and thus compacted `by a pressure fan which latter has been found in practice to retard proper heating of the air during passage through the furnace.

'A furtherobject is to provide apparatus of -this character which will be formed of a few strong, simple and durable parts, which will be inexpensive to manufacture, and which willV not easily get out of order.

With the above and other objects in view the invention consists of -certain novel details of construction and combinations of parts hereinafter fully described and claimed, it being understood-that various medmeations maybe resorted to within the scope of the appended claims without departing from the spirit orA sacrificing anyl of the advantages of the invention.

In the accompanying drawings forming part of this speciication: v

Figure 1 is a transverse sectional vview of a hot air furnace constructed in accordance with the invention and taken on the line I-I of Figure 2 isa lengitudimu 'sectional lview ofV the hot air furnace taken on the line 2-201 mure 1'.' Y K Y v' Figure 3 is a. horizontal sectional view of the hot air furnace taken on the line 3-3 of Figure-2. Figure 4 is a plan view of the blank from which one of the sections vofthe radiant combustio chamber is formed. I

tion chamber II the `vWall ofwhich is constructed of sections I2 hereinafter more fully described in detail. The combustion chamber extends the length of the casing and is spaced from the sides of' the casing, access to the combustion chamber being had through a removable plate I3, best shown in Figure 2. The flrepot is supported upon legs I4, best-shown in Figure 1, and the bottom portion of the casing is divided longitudinally by division walls I5 disposed adjacent the legs to provide air ducts I6, I'I and I8, the center air duct communicating .with the Y combustion chamber through openings I9 formed in a grille 20' which extends transversely of the bottom portion cf the casing and also co-acts in supporting the combustion chamber. 'I'he center air duct I1 supplies air for combustion to I the top of the furnace casingA and forms the bottom of a cold air return flue 25 through which cold air is drawn downwardly through the casl ing and through the openings I9 in the bottom v grille20 and into the hot'air ducts I6 'and I8v for supplying the rooms to be heated. y

Disposed within the casing I0 above the' comtion upwardly in a circuitous zigzag path from f the combustion chamber to a header 21 extending longitudinally of the casing near the top thereof andadapted to be connected to the chimney. Each atube comprises superposed horizontal porftions 28 extending from side to side of the casing andconnected at their ends by elbows 29, as

Y This arrangement of the tubes assures of 1 the down air draft becombest shown in FigureV 1.

thoroughly heated and uniformly heated throughout every partV of the furnace.

A plurality of water containers 30 are disposed V inthe casing Il and are connected by a supply' pipejl, best shown in 1. The water be used.

supply in the containers for humidifying the heated air is automatically controlled by a valve 32 operated by a float 33 in a supply tank 34 disposed outside of the casing III, the valve controlling a water supply pipe in the usual manner. A drain pipe 36 extends downwardly from the header 21 to catch condensation. The header is bolted to the casing as shown at 4I. Other means connecting the As best shown in Figure 3, the air ducts I6 and bars of the frame together mayv I8 of the furnace are extended outwardly beyond the furnace as shown at 42 and 43, the-extended portions of the air ducts converging at the intake end 44 of the conventional blower 45 having a driving pulley. whichy may be driven from anysuitable source of`power. The outlet duct 41 of the blower conductsrthe heated humidiiied air lfrom the furnace to the room to be heated.

The wall of the combustion chamber is coniings61 in the ends of the sections. These iins radiate heatfrom the horizontal portions ofthe tubes to uniformly heat the air draft passing downwardly in' the furnace over the tubes.-

The elbows 29 of each tube 26 likewise are provided with `fins designated in general by-the numeral 68 and .these ns are a duplicate of the iins just described, only larger to encircle the elbows, so that a detailed description willnot be given.

Since the operation of thel parts has been described as a description of the parts progressed, it is thought the invention will be fully understood Without further explanation;

What is claimed is: Y

1. A hot air furnace, comprising a casing, a restricted air supply channel across the upper end of the casing, a combustion chamber in the lower end of the casing and havingA itsl upper end formed of converging wall membersconneeted by a horizontal top Wall, a plurality of tubes connected to the conical upper end of the combustion chamber with superimposed horizonxtal convolutions, a headerv extending across the posed of sections each formed from a single blank slit.- Between the score lines 50 and 5I a row of openings 54 is formed and between the score lines 52 and 53 a row of openings 55 is formed.

The blank shown in Figure 4 is bent at the slits 49 to form an inclined top wall section 56 l of the combustion chamber asy shown in Figure 1 and to form a vertical side wall section 51 as also shown in this figure. The blank is bent along the score lines to provide diverging fins 58, as best shown in Figure 3. The blank is also bent along the score lines to provide straight flanges 59. In assembling the `combustion chamber the flanges 59 of each two adjacent vertical sections I2 have the rows of openings `54 and 55 in alinement and through these alined openings securing bolts 60 are passed toassemble the sections. The inclined top wall portions 56 of the sections are connected by a top' plate 6I, best shown in Figure l, through which top plate the lower ends of the tubes 26 communicate with the combustion chamber.

A flame spreader 62 is secured in the combustion chamber between the bar of radiants 2I to spread the flame against the inclined sections 56 of the'flrepot.

The horizontal portions 28 of the tubes 26 are .provided with fins, one of which is shown in casingbelow and spaced from the air supply channel, and having the tubes connected to the sides thereof, and. air ducts communicating'with the casing at each side thereof below the lower end of the combustion chamber.

2. A hot; air furnace, comprising a casing, a

restricted airl supply channel vacross the upper en'd of the casing and having openings communieating therewith, a combustion chamber centrally located in the casing above the lower end thereof and provided with its upper end formed of converging wall members connected byra horizontal top wall, a plurality of tubes connected to the horizontal top wall end of the combustion chamber with superimposed horizontal convolutions, a header extending across the casing below and spaced from the air supplychannel.

l restricted air supply channel across the upper end of the casing and communicating therewith, a combustion chamber within the casing above the lower end thereof with its upper end formed of converging wall members connected by a horizontal top wall, a plurality oftubes connected to the horizontal top wall of the combustion chamber withV superimposed horizontal convolutions, a header extending across the upper end ofthe casing below the air supply channel and spaced therefrom and 'having one end connected to a. v

flue, the horizontal convolutions of the tubes connected to the sides of the header, a heater in the 'combustion chamber, a passage below the combustion chamber for supplying air to the the other section. 'Iheiianges are adapted to extend beyond the horizontal portions 28 of the tubes, as best shown in Figure 2. To assemble the sections bolts 66 are passed through openheater, and an air discharge passage communieating with the casing on each side of the air supply passage for the heater and converging into a single discharge opening.

CLIFFORD BLAIR. 

